There are many cooking appliances in homes today, such as slide in ranges, free standing ranges, and other appliances, that have cook tops. Many of these cooking appliances have holes in the maintop of the cook top through which shafts extend. These shafts can be, for example, shafts of gas valves on which control knobs are mounted. Some of these cook tops develop a combustion air airflow that flows past the control knobs and, in doing so, creates a negative air pressure around and below the control knobs. This negative air pressure can cause hot air that exists below the maintop to be pulled up through the holes in the maintop. As the hot air is pulled up through the holes, it can pass over the control knobs and undesirably raise the temperature of the control knobs.
Accordingly, an improved system is desired for effectively preventing the passage of hot air from below the maintop through the holes in the maintop.